#include <stdio.h>
#include <string.h>

int main(){
    char a[5]="abc";
    char b[5]="def";
    printf("%zd,%zd\n",sizeof(a),sizeof(b));
    printf("%zd,%zd\n",strlen(a),strlen(b));
    strcat(a,b);
    printf("%zd,%zd\n",sizeof(a),sizeof(b));
    printf("%zd,%zd\n",strlen(a),strlen(b));
    puts(a);
    puts(b);
}
